Oscar nominees are selected by a process more democratic than the one we use to elect legislators.
As much as you enjoyed Aeon Flux, you know it can't win. You enjoyed Brokeback Mountain almost as much, and you know it stands a chance. Under choice voting, the system used by the Academy, you can still register a vote for Aeon Flux without hurting Brokeback Mountain.
LA Times' "The Envelope" explains how it works.